RE: [lwip-users] updated raw api UDP echo server example

[Goldschmidt Simon]

> >> > One question remains: I use multicast and bind the pcb to a 
> >> > multicast-address.
> >> > So when sending, as src.ip the multicast addr is used. 
> Any ideas to 
> >> > solve that in a nice way?
> >> 
> >> Hmm, other than directly manipulating the pcb I would say:
> >> use another pcb and do a second udp_bind() to your real IP address 
> >> and use this pcb to send the outgoing packets...
> > 
> > I don't know if that works, as two pcbs would have to be 
> bound to the 
> > same port. I think there's a todo for that kind of usage.
> 
> If I read the code (1.2.0) correctly, it is not tested in 
> udp_bind(), even though there is code to test it, but this is 
> disabled via #ifdef LWIP_UDP_TODO, which is not set anywhere. 
> But even then the mentioned code would allow binding to 
> multicast and one(!) IP address, but not to multicast and IP_ADDR_ANY.
> 
> So, iow the second call to udp_bind() should at least 
> succeed, but if it really works remains to be tested.
> 
> Dominik, your turn ;)

As I said, I don't know. Task #6995 and bug #2809 tell me that
we would need SO_REUSEADDR for that...


Simon.